Vodafone — My plan 299 chaned to 399 with out my consent

Iam from Andhra Pradesh and customer of vodofone postpaid with no [protected]. Till now iam using 299 Monthly plan and now suddenly i received a message today that i requested for 399 monthly plan and it is activated from today. This is just looting with out customer consent. For your kind information i did not requested for change of my plan. Please withdraw 399 monthly plan and convert my plan to 299 monthly postpaid which iam using till now.